Ameliorating substance accessibility for microorganisms to amplify toluene degradation and power generation of microbial fuel cell by using activated carbon anode

Abstract

Limited access to the hydrophobic organic compounds by microorganisms impedes the improvement of performance of bioreactor processing contaminant degradation. Here, we assembled activated carbon in the anode chamber of the microbial fuel cell (MFC) to serve as a reservoir for toluene molecular and exoelectrogens. The adsorption of toluene by activated carbon facilitated the substrate accessible by exoelectrogens and was beneficial for toluene biodegradation. Rapid degradation of toluene was achieved by MFC assembled with active carbon anode (AC-MFC) in 36 h, which was shorter than that (∼60 h) for MFC with carbon felt anode (CF-MFC). In addition, significant decrease of gaseous toluene released from anolyte into headspace as the introduction of activated carbon. The model EABs Geobacter anodicances was enriched on activated carbon, which brought out the elevated performance of AC-MFC for toluene degradation and power generation. Polarized curves revealed that the maximum power density of AC-MFC was 3328 mW/m3, which was 2.6 times higher than that of CF-MFC (1267 mW/m3). Analysis of anolyte revealed that benzoic acid, dihydroxybenzoic acid and β-carboxy-cis-cis-muconate were the main intermediate products during toluene degradation. This work provides an effective strategy for improving biodegradation efficiency of hydrophobic organic compounds accompany with power generation.